1. Field of the Invention
The present invention relates to a color image processing apparatus for processing color image data so as to obtain data which are necessary for forming a color image.
2. Related Background Art
The applicant has already proposed, in the specification of U.S. Pat. No. 4,204,728, a color copying apparatus which is capable of conducting conversion between a predetermined number of colors which are combinations of R, G and B colors. This color copying apparatus, however, is not suitable for use in the field of graphic designing because the number of colors available for the color conversion is limited. In order to obviate this shortcoming, the applicant also has proposed, in the specification of the U.S. patent application Ser. No. 084,080 filed on Aug. 11, 1987, a copying apparatus capable of conducting color conversion between a greater number of colors.
The color copying apparatus, however, suffers from the following disadvantage. The conversion from a first color into a second color is conducted by appointing these colors in terms of color information. In this operation, the color information which identifies the first color is used as a reference and all the colors with information falling within a predetermined range around the reference color information are regarded as being the same as the first color so that all these colors are converted into the second color. In consequence, problems are encountered such as failure in the conversion of the desired color or conversion of a color which the user does not wish to convert. This drawback is attributable to the fact that, while the ranges of colors which the user wishes to convert vary depending on factors such as the type of the document, intension of the user, and so forth, the copying apparatus employs fixed tolerances of hue and color density so that it regards and processes all the colors having hues and color densities falling within the fixed tolerances from those of the appointed color as being the same as the appointed color.